When cancer cells are formed, they are known to appear in due course in blood and biological fluid. Such cancer cells in blood are called “circulating tumor cells (CTCs)”. Thus, it is expected that the circulating tumor cells can be examined, e.g., to confirm the cancer-treating effect, predict prognosis life expectancy, predict the effect of anticancer drugs before administration, or examine treatment methods through genetic analysis of cancer cells.
However, a problem exists in that since the number of circulating tumor cells is very small (several to hundreds of cells/1 mL of blood), such cancer cells are difficult to capture.
For example, the CellSearch System is known as a technique for capturing circulating tumor cells. This technique, which utilizes an antigen-antibody reaction (capture by EpCAM antibody), can only capture cancer cells expressing EpCAM, and the types of capturable cancer cells are limited.